Methods and apparatus for presbyopia treatment using a dual-function laser system

Abstract

Presbyopia is treated by a method which uses various lasers to remove a portion of the scleral tissue and increase the accommodation of the presbyopic patient's eye By changing the laser power density, fluency or spot size, a single laser device having dual-function of ablation and coagulation is proposed for minimum bleeding. Fiber-bundle coupled to a single fiber is presented to increase the power density of the laser for efficient tissue ablation New mechanisms of lens curvature change and lens anterior shift are proposed for the total accommodation. The preferred laser wavelength ranges from ultraviolet to infrared including (0.15-0.36) microns, (0.9-1.6) microns, (1.8-2.2) microns and (2.8-3.2) microns Both scanning and fiber delivered systems are proposed.

Description

[0001] 1. Field of the Invention[0002] The present invention relates to apparatus and methods for the treatment of presbyopia using fiber-coupled, dual-function lasers to ablate and coagulate the sclera tissue[0003] 2 Prior Art[0004] When a person reaches a certain age (around 45), the eyes start to lose their capability to focus sharply for near vision. Presbyopia is not due to the cornea but comes about as the lens loses its ability to accommodate or focus sharply for near vision as a result of loss of elasticity that is inevitable as people age. The existing vision correction methods are mainly for the treatment of myopia, hyperopia and astigmatism by reshaping the cornea surface Wearing bifocal lens (glasses) has been the major means for the correction of presbyopia, although some surgical methods have been used in clinical trials.[0005] Prior art of Sand's patent (U.S. Pat. No. 5,484,432) uses a thermal laser with spectrum of (1.80-2.55) run to shrink the corneal shape (inside ...

AI Technical Summary

Benefits of technology

[0011] It is yet another objective of the present invention to use one "single" laser unit to achieve dual function of ablation and coagulation when soft tissue is ablated such that presbyopia treatment can be conducted with minimum bleeding and procedure can be done faster without the use of bipolar device

[0015] The preferred embodiments of the present surgical laser consists of a combination of an ablative-type laser and a delivery unit The ablative-type laser preferred to have a wavelength range of (015 to 035) um, or (095-16) um, or (185-32) um or (4-10) um and should be operated in a pulsed mode such that the thermal damage of the ablated tissue is minimized.

[0019] It is yet another embodiment of the present surgical method that a novel method which combines fiber bundles from diode lasers and re-focused to a smaller single fiber to increase the power density

[0020] It is yet another embodiment of the present surgical laser to provide an integration system in which the sclera ablation leads to the increase of the accommodation of the ciliary muscle for the treatment of presbyopia and for the prevention of open angle glaucoma.

Problems solved by technology

To treat presbyopic patients, or the reversal of presbyopia, using the concept of expanding the sclera by mechanical devices has been proposed by Schachar in U.S. Pat. Nos. 5,489,299, 5,722,952, 5,465,737 and 5,354,331 These mechanical approaches have the drawbacks of complexity and are time consuming, costly and have potential side effects.

However, these prior arts do not present any details or practical methods or laser parameters for the presbyopic corrections No clinical studies have been practiced to show the effectiveness of the proposed concepts by Schachar and many of his proposed lasers are thermal lasers which will cause thermal burning of the cornea, rather than tissue ablation.

It requires a deep (90%-98%) cut of the sclera tissue in order to obtain accommodation of the lens This method, however, involves a lot of bleeding and is difficult to control the depth of the cut which requires extensive surgeon's skill

Lin's prior arts in U.S. Pat. No. 6,258,082 proposed the use ablative lasers to ablate scleral tissue and cause the increase of the elasticity of the sclera-ciliary-zonules complex for improved accommodation of presbyopic patients One of the major drawbacks of surgical method for the treatment of presbyopia is the inevitable bleeding which occurs when cutting the conjunctival or scleral tissue Conventionally, this bleeding requires electrode device such as bipolar to stop Another prior art of Lin in U.S. Pat. No. 6,263,879, proposed a "dual-laser" system using an ablative laser and a coagulative laser for the treatment of presbyopia This prior art, however requires a scanning device and combining of two different lasers to achieve ablation and coagulation effects These two lasers are also required to interact with the tissue in a totally different nature, one "cold" and one "thermal", which are difficult and costly to make for practical applications

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